The present invention relates to medical uses of a recombinant Ganoderma Lucidum Immunoregulatory Protein (rLZ-8) for anti-tumor, increase of the number of leucocyte and inhibiting immunological rejection, etc. The protein gene sequence was originated from Ganoderma Lucidum and redesigned such that it was more suitable for recombinant expression by eukaryote expression system of Pichia pastoris. Crystal structure (tertiary and quatemary structures) of rLZ-8 was obtained by X-ray diffraction, analysis was performed based on the combination of said crystal structure and relevant functions thereof, a conclusion was drawn that any protein molecule having said structure has the foresaid medical uses, this has already been verified by large number of in vivo and in vitro pharmacodynamic studies. In conclusion, the recombinant Ganoderma Lucidum Immunoregulatory Protein (rLZ-8) of the present invention can be used as an anti-tumor drug or a increase of the number of leukocyte drug or an immunoinhibitor.